U.S. Pat. No. 8,227,560 reports on methods and polymers based upon vinyl type monomers that contain pendant carboxylic acid groups and ester group functionality, such as the polymerization of itaconic acid. The polymers are prepared under selected conditions of partial neutralization to provide relatively high conversions and/or relatively high values of molecular weight and/or selected amounts of repeating unit tacticity.
U.S. Pat. No. 8,410,232 reports on esters of itaconic acid as suitable for polymerization in aqueous medium in the presence of seed particles. The seed particles were indicated as absorbing the monomer and polymerizing to a desired particle size.
The sensitivity of polymerizing esters of itaconic acid to its polymerization media has been evaluated by Hirano et al, who reported on a pronounced dependence of stereospecificity in the radical polymerization of dibutyl itaconate (DBI) on polymerization temperature. T. Hirano, S. Tateiwa, M. Seno and T. Sato, Journal of Polymer Science Part A: Polymer Chemistry Volume 38, Issue 13, pages 2487-2491, 1 July 2000. More specifically, the bulk polymerization and formation of poly(dibutyl itaconate) was studied and showed a temperature dependence of tacticity. In subsequent studies, it was determined that radical polymerization of di-n-butyl itaconate indicated unexpected resonances (C-resonances) in 13C NMR spectra at temperatures higher than 60° C., the presence of intramolecular chain transfer which took place more frequently at high temperature in the polymerization of itaconates with bulkier ester groups. See, Tomohiro Hirano, Kazuhiro Furuya, Makiko Seno and Tsuneyuki Sato, Journal of Polymer Science Part A: Polymer Chemistry Volume 40, Issue 24, pages 4513-4522, 15 Dec. 2002, “13C NMR and Electron Spin Resonance Analyses of the Radical Polymerization of Diisopropyl Itaconate” and Tomohiro Hirano, Ryoko Takeyoshi, Makiko Seno and Tsuneyuki Sato, Journal of Polymer Science Part A: Polymer Chemistry Volume 40, Issue 14, pages 2415-2426, 15 Jul. 2002, “Chain-Transfer Reaction in the Radical Polymerization of Di-n-butyl Itaconate at High Temperatures.” In addition, radical polymerization of dibutyl itaconate was examined in the presence of amide compounds that could complex with DBI monomer via hydrogen-bonding interaction, which was described to result in a change in the population of the propagating radical with a syndiotactic sequence. See, Tomohiro Hirano, Kousuke Higashi, Makiko Seno and Tsuneyuki Sato, Journal of Polymer Science Part A: Polymer Chemistry Volume 41, Issue 21, pages 3463-3467, 1 Nov. 2003, “Effect of Hydrogen-Bonding Interaction on Radical Polymerization of Di-n-butyl Itaconate” and Tomohiro Hirano*, Kousuke Higashi, Makiko Seno and Tsuneyuki Sato, Journal of Polymer Science Part A: Polymer Chemistry Volume 42, Issue 19, pages 4895-4905, 1 October 2004, “Reaction Control in Radical Polymerization of Di-n-butyl Itaconate Utilizing a Hydrogen-Bonding Interaction.”
In view of the relatively highly sensitive nature of itaconate ester monomers to polymerizing conditions in the bulk, one objective herein was to consider the use of emulsion polymerization with associated temperature control to determine if an emulsion environment could provide poly(alkylitaconates) at selected particle size, free acidic content, relatively high molecular weight, relatively high conversion and/or relatively high levels of syndiotactic placement.